Non-contact seal with resilient biasing element(s)

ABSTRACT

A seal device includes a plurality of seal shoes, a seal base, a plurality of spring elements and a resilient biasing element. The seal shoes are arranged around an axis. The seal base circumscribes the seal shoes. Each of the spring elements is radially between and connects a respective one of the seal shoes and the seal base. A first of the spring elements includes a first mount, a second mount and a spring beam. The first mount is connected to a first of the seal shoes. The second mount is connected to the seal base. The spring beam connects the first mount to the second mount. The resilient biasing element is radially between and engaged with first and second components of the seal device, where the first component is configured as or otherwise includes the first mount or the second mount.

This invention was made with government support under Contract No.FA8626-16-C-2139 awarded by the United States Air Force. The governmentmay have certain rights in the invention.

BACKGROUND 1. Technical Field

This disclosure relates generally to rotational equipment and, moreparticularly, to a non-contact seal assembly for rotational equipment.

2. Background Information

Rotational equipment such as a gas turbine engine typically includes aseal assembly for sealing an annular gap between a rotor and astationary structure. Various types and configurations of sealassemblies are known in the art. While these known seal assemblies havevarious advantages, there is still room in the art for improvement.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present disclosure, an assembly isprovided for rotational equipment. This assembly includes a seal device.The seal device includes a plurality of seal shoes, a seal base, aplurality of spring elements and a resilient biasing element. The sealshoes are arranged around an axis in an annular array. The seal basecircumscribes the annular array of the seal shoes. Each of the springelements is radially between and connects a respective one of the sealshoes and the seal base. A first of the spring elements includes a firstmount, a second mount and a spring beam. The first mount is connected toa first of the seal shoes. The second mount is connected to the sealbase. The spring beam connects the first mount to the second mount. Theresilient biasing element is radially between and engaged with first andsecond components of the seal device, where the first component isconfigured as or otherwise includes the first mount or the second mount.

According to another aspect of the present disclosure, another assemblyis provided for rotational equipment. This assembly includes a sealdevice. The seal device includes a plurality of seal shoes, a seal base,a plurality of spring elements and a spring. The seal shoes are arrangedaround an axis. The seal base extends circumferentially around the sealshoes and the spring elements. Each of the spring elements connects arespective one of the seal shoes to the seal base. A first of the springelements includes a first mount, a second mount and a plurality ofspring beams. The first mount is connected to a first of the seal shoes.The second mount is connected to the seal base. Each of the spring beamsconnects the first mount to the second mount. The spring is abuttedagainst first and second components of the seal device, where the firstcomponent is configured as or otherwise includes the first mount or thesecond mount.

According to still another aspect of the present disclosure, anotherassembly is provided for rotational equipment. This assembly includes aseal device. The seal device includes a plurality of seal shoes, a sealbase, a plurality of spring elements and a spring. The seal shoes arearranged around an axis. The seal base extends circumferentially aroundthe seal shoes and the spring elements. Each of the spring elementsconnects a respective one of the seal shoes to the seal base. A first ofthe spring elements includes a first mount, a second mount and aplurality of spring beams. The first mount is connected to a first ofthe seal shoes. The second mount is connected to the seal base. Each ofthe spring beams connects the first mount to the second mount. Thespring is abutted against first and second components of the sealdevice. The spring is configured to increase a stiffness of the first ofthe spring elements. The first component is configured as or otherwiseincludes the first mount or the second mount.

The resilient biasing element may be configured to increase a stiffnessof the first of the spring elements.

The resilient biasing element may be configured to bias a first portionof the first of the seal shoes radially away from the seal base and asecond portion of the first of the seal shoes radially towards the sealbase.

The resilient biasing element may be configured as or otherwise includea spring.

The resilient biasing element/the spring may be configured as orotherwise include a coil spring.

The first component may be configured as or otherwise include the firstmount. The second component may be configured as or otherwise includethe seal base.

The first component may be configured as or otherwise include the firstmount. The second component may be configured as or otherwise include amount of a second of the spring elements that is circumferentiallyadjacent to the first of the spring elements.

The first mount may be configured as or otherwise include an innersurface. The mount of the second of the spring elements may beconfigured as or otherwise include an outer surface radially below theinner surface. The resilient biasing element may be radially between andengage the inner surface and the outer surface.

The mount of the second of the spring elements may be configured as orotherwise include a second mount. The second of the spring elements mayalso include a first mount and a spring beam. The first mount of thesecond of the spring elements may be connected to a second of the sealshoes. The second mount of the second of the spring elements may beconnected to the seal base. The spring beam of the second of the springelements may connect the first mount of the second of the springelements to the second mount of the second of the spring elements.

The first component may be configured as or otherwise include the secondmount. The second component may be configured as or otherwise includethe first of the seal shoes.

The second mount may be configured as or otherwise include an innersurface. The first of the seal shoes may be configured as or otherwiseinclude an outer surface radially below the inner surface. The resilientbiasing element may be radially between and engage the inner surface andthe outer surface.

The first of the seal shoes may be configured as or otherwise include aninner surface. The second mount may be configured as or otherwiseinclude an outer surface radially below the inner surface. The resilientbiasing element may be radially between and engage the inner surface andthe outer surface.

The first component may be configured as or otherwise include the firstmount. The seal device may also include a second resilient biasingelement engaged with the second mount.

The seal device may also include a second resilient biasing elementengaged with the first component.

The first of the spring elements may also include a second spring beamconnecting the first mount to the second mount.

The assembly may also include a ring structure and a secondary sealdevice. The ring structure may be axially engaged with the seal base.The secondary seal device may be mounted with the ring structure. Thesecondary seal device may be configured to substantially seal an annulargap between the ring structure and the annular array of the seal shoes.

The assembly may also include a stationary structure, a rotor structureand a non-contact seal assembly. The non-contact seal assembly may beconfigured as or otherwise include the seal device. The seal assemblymay be configured to substantially seal an annular gap between thestationary structure and the rotor structure. The seal shoes maycircumscribe and sealingly mate with the rotor structure. The seal basemay be mounted to and radially within the stationary structure.

The foregoing features and the operation of the invention will becomemore apparent in light of the following description and the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial side sectional illustration of an assembly forrotational equipment.

FIG. 2 is a perspective illustration of a primary seal device of anon-contact seal assembly.

FIG. 3 is a partial side sectional illustration of the primary sealdevice.

FIG. 4 is an end illustration of a section of the primary seal device.

FIG. 5 is a segmented end illustration of the primary seal devicesection of FIG. 4.

FIG. 6 is a perspective illustration of a portion of the primary sealdevice section of FIG. 4.

FIGS. 7-9 are schematic illustrations of other portions of a primaryseal device configured with resilient biasing elements.

FIG. 10 is a side cutaway illustration of a geared gas turbine engine.

DETAILED DESCRIPTION

FIG. 1 illustrates an assembly 20 for rotational equipment with an axis22 of rotation; i.e., a rotational axis. An example of such rotationalequipment is a gas turbine engine for an aircraft propulsion system, anexemplary embodiment of which is described below in further detail.However, the assembly 20 of the present disclosure is not limited tosuch an aircraft or gas turbine engine application. The assembly 20, forexample, may alternatively be configured with rotational equipment suchas an industrial gas turbine engine, a wind turbine, a water turbine orany other apparatus in which a seal is provided between a stationarystructure and a rotor.

The assembly 20 of FIG. 1 includes a stationary structure 24, a rotorstructure 26 and a non-contact seal assembly 28. The seal assembly 28 ismounted with the stationary structure 24 and configured to substantiallyseal an annular gap 30 between the stationary structure 24 and the rotorstructure 26 as described below in further detail.

The stationary structure 24 includes a seal carrier 32. This sealcarrier 32 may be a discrete, unitary annular body and removablyattached to another component 33 of the stationary structure 24.Alternatively, the seal carrier 32 may be configured with anothercomponent/portion of the stationary structure 24; e.g., the components32 and 33 may be integrally formed. The seal carrier 32 has an innerradial seal carrier surface 34. This seal carrier surface 34 may besubstantially cylindrical, and extends circumferentially around andfaces towards the axis 22. The seal carrier surface 34 at leastpartially forms a bore in the stationary structure 24. This bore issized to receive the seal assembly, which may be fixedly attached to theseal carrier 32 by, for example, a press fit connection between the sealassembly and the seal carrier surface 34. The seal assembly, of course,may also or alternatively be fixedly attached to the seal carrier 32using one or more other techniques/devices.

The rotor structure 26 includes a seal land 36. This seal land 36 may bea discrete, unitary annular body. Alternatively, the seal land 36 may beconfigured with another component/portion of the rotor structure 26. Theseal land 36 has an outer radial seal land surface 38. This seal landsurface 38 may be substantially cylindrical, and extendscircumferentially around and faces away from the axis 22. The seal landsurface 38 is disposed to face towards and is axially aligned with theseal carrier surface 34. While FIG. 1 illustrates the seal land surface38 and the seal carrier surface 34 with approximately equal axiallengths along the axis 22, the seal land surface 38 may alternatively belonger or shorter than the seal carrier surface 34 in other embodiments.

The seal assembly 28 includes a primary seal device 40 and one or moresecondary seal devices 42. The seal assembly 28 also includes one ormore additional components for positioning, supporting and/or mountingone or more of the seal devices with the stationary structure 24. Theseal assembly 28 of FIG. 1, for example, includes a first ring structure44 configured for positioning, supporting and/or mounting the secondaryseal devices 42 relative to the primary seal device 40. This first ringstructure 44 may also be configured for axially positioning and/orsupporting a first end surface 46 of the primary seal device 40 relativeto the stationary structure 24. The seal assembly 28 of FIG. 1 alsoincludes a second ring structure 48 (e.g., a scalloped supportring/plate) configured for axially positioning and/or supporting asecond end surface 50 of the primary seal device 40 relative to thestationary structure 24. However, the second ring structure 48 may beomitted where, for example, the second end surface 50 of the primaryseal device 40 is abutted against another component/portion of thestationary structure 24 (e.g., an annular or castellated shoulder) orotherwise axially positioned/secured with the stationary structure 24.

Referring to FIG. 2, the primary seal device 40 is configured as anannular non-contact seal device and, more particularly, a hydrostaticnon-contact seal device. An example of such a hydrostatic non-contactseal device is a HALO™ type seal; however, the primary seal device 40 ofthe present disclosure is not limited to the foregoing exemplaryhydrostatic non-contact seal device.

Referring to FIGS. 3 and 4, the primary seal device 40 includes a sealbase 52, a plurality of seal shoes 54, a plurality of spring elements56. The primary seal device 40 also includes a plurality of resilientbiasing elements 57 configured to increase stiffness between the sealshoes 54 and the seal base 52 as described below in further detail.

The seal base 52 is configured as an annular full hoop body (see FIG.2), which extends circumferentially around the axis 22. The seal base 52is configured to circumscribe and support the seal shoes 54 as well asthe spring elements 56. The seal base 52 extends axially along the axis22 between and forms the first end surface 46 and the second end surface50. The seal base 52 extends radially between an inner radial base side58 and an outer radial base side 60. The outer radial base side 60radially engages (e.g., is press fit against) the stationary structure24 and, more particularly, the seal carrier surface 34 (see FIG. 1).

Referring to FIG. 2, the seal shoes 54 are configured as arcuate bodiesand arranged circumferentially about the axis 22 in an annular array.This annular array of the seal shoes 54 extends circumferentially aroundthe axis 22, thereby forming an inner bore at an inner radial side 62 ofthe primary seal device 40. As best seen in FIG. 1, the inner bore issized to receive the seal land 36, where the rotor structure 26 projectsaxially through (or into) the inner bore formed by the seal shoes 54.

Referring to FIG. 4, each of the seal shoes 54 extends radially from theinner radial side 62 of the primary seal device 40 to an outer radialsurface 64 of that seal shoe 54. Each of the seal shoes 54 extendscircumferentially around the axis 22 between opposing first and secondcircumferential sides 66 and 68 of that seal shoe 54.

Referring to FIG. 3, each of the seal shoes 54 extends axially along theaxis 22 between a first shoe end 70 and a second shoe end 72. The firstshoe end 70 may be axially offset from and project axially away from thefirst end surface 46. The second shoe end 72 may be axially aligned withthe second end surface 50. The seal shoes 54 of the present disclosure,however, are not limited to such exemplary relationships.

Each of the seal shoes 54 includes an arcuate end surface generally at(e.g., on, adjacent or proximate) the first shoe end 70. In the array,these arcuate end surfaces collectively form a generally annular (butcircumferentially segmented) end surface 74 configured for sealinglyengaging with the secondary seal devices 42; see FIG. 1. The seal shoes54 of the present disclosure, however, are not limited to the foregoingexemplary configuration.

Each of the seal shoes 54 includes one or more arcuate protrusions,which collectively form one or more (e.g., a plurality of axiallyspaced) generally annular (e.g., circumferentially segmented) ribs 76 atthe inner radial side 62. Distal inner radial ends of one or more ofthese ribs 76 are configured to be arranged in close proximity with (butnot touch) and thereby sealingly mate with the seal land surface 38 in anon-contact manner (see FIG. 1), where the rotor structure 26 projectsaxially through (or into) the inner bore formed by the seal shoes 54. Inthe embodiment of FIG. 3, each of the ribs 76 has the same radialheight. In other embodiments, however, one or more of the ribs 76 mayhave a different radial height than at least another one of the ribs 76.

Referring to FIG. 2, the spring elements 56 are arrangedcircumferentially about the axis 22 in an annular array. Referring againto FIGS. 3 and 4, the spring elements 56 are also arranged radiallybetween the seal shoes 54 and the seal base 52. Each of the springelements 56 is configured to moveably and resiliently connect arespective one of the seal shoes 54 to the seal base 52.

The spring element 56 of FIG. 4 includes first and second mounts 78 and80 (e.g., radial fingers/projections) and one or more spring beams 82.Referring to FIG. 5, the first mount 78 is connected to a respective oneof the seal shoes 54 at (e.g., on, adjacent or proximate) the firstcircumferential side 66, where the opposing second circumferential side68 of that seal shoe 54 is free floating. The first mount 78 of FIG. 5includes a first mount base 84 and a first mount lip 86. The first mountbase 84 projects radially out from the respective seal shoe 54 to adistal radial outer surface 88 of the first mount 78. The first mountbase 84 is disposed circumferentially between the spring beams 82 andthe first mount lip 86. The first mount lip 86 projects laterally (e.g.,circumferentially or tangentially) out from the first mount base 84. Thefirst mount lip 86 extends radially inward from the outer surface 88 toa radial inner surface 90 of the first mount 78.

The outer surface 88 and the inner surface 90 are configured as stopsfor the respective seal shoe 54. More particularly, each surface 88, 90is configured to restrict (e.g., limit) radial movement of therespective seal shoe 54 proximate the first mount 78. For example,interaction (e.g., contact) between the outer surface 88 and anotherfeature such as the resilient biasing element 57 (or alternatively thesurface of the seal base 52) will restrict how far the respective sealshoe 54 can move radially outward. Similarly, interaction (e.g.,contact) between the inner surface 90 and another feature such as aradially outer surface 92 of the second mount 80 of an adjacent springelement 56 will restrict how far the respective seal shoe 54 can moveradially inward.

The second mount 80 is connected to the seal base 52, and is generallycircumferentially aligned with or near the second circumferential side68. The second mount 80 therefore is disposed a circumferential distancefrom the first mount 78.

The second mount 80 of FIG. 5 includes a second mount base 94, a secondmount flange 96 and one or more second mount lips 98 and 100. The secondmount base 94 projects radially inward from the seal base 52 to a radialinner surface 102. The second mount flange 96 is laterally adjacent theinner surface 102. The second mount flange 96 projects radially inwardsfrom the seal base 52 to a distal radial inner surface 104 of the secondmount 80. The second mount flange 96 is disposed laterally between thesecond mount lips 98 and 100. The second mount lip 98 projects laterallyout from the second mount flange 96. The second mount lip 98 extendsradially outward from the inner surface 104 to a radial outer surface106 of the second mount 80. The second mount lip 100 projects laterallyout from the second mount flange 96. The second mount lip 100 extendsradially outward from the inner surface 104 to the outer surface 92 ofthe second mount 80.

The outer surface 106 and the inner surface 102 are configured as stopsfor the respective seal shoe 54. More particularly, each surface 106,102 is configured to restrict (e.g., limit) radial movement of therespective seal shoe 54 proximate the second mount 80. For example,interaction (e.g., contact) between the outer surface 106 and anotherfeature such as a radial inner surface 108 of a lipped flange 109 of therespective seal shoe 54 will restrict how far the respective seal shoe54 can move radially inward. Similarly, interaction (e.g., contact)between the inner surface 102 and another feature such as a radial outersurface 110 of the lipped flange 109 will restrict how far therespective seal shoe 54 can move radially outward.

The spring beams 82 are configured as resilient biasing members of theprimary seal device 40. The spring beams 82 of FIG. 4, for example, aregenerally configured as cantilevered-leaf springs. These spring beams 82are radially stacked and spaced apart with one another so as to form afour bar linkage with the first mount 78 and the second mount 80. Moreparticularly, each of the spring beams 82 is connected to the firstmount 78 and the second mount 80. Each of the spring beams 82 extendslongitudinally (e.g., in a generally circumferential direction relativeto the axis 22) between and to the first mount 78 and the second mount80. The spring beams 82 of FIG. 4 may thereby laterally overlap a majorcircumferential portion (e.g., ˜65-95%) of the respective seal shoe 54.

The spring beams 82 are configured to provide the respective springelement 56 with a certain spring stiffness. This spring stiffness isselected in order to reduce internal stress within the spring beams 82while also providing the respective spring element 56 with a relativelyhigh natural frequency. However, reducing internal spring beam stressmay lower the natural frequency of the respective spring element 56.Therefore, in order to enable relatively low spring beam stress, theresilient biasing elements 57 are provided.

Each resilient biasing element 57 is configured to enhance (e.g.,increase) the spring stiffness of the respective spring element 56 bybiasing a first portion 111 of the respective seal shoe 54 radiallyinward and away from the seal base 52, where the first portion 111 isgenerally circumferentially aligned with the element 57. This resilientbiasing element 57 also biases a second portion 113 of the respectiveseal shoe 54 radially outward and towards the seal base 52, where thesecond portion 113 is circumferentially offset from the element 57. Eachresilient biasing element 57 is also configured to provide support forthe first circumferential side 66 of that seal shoe 54. As a result, oneor more of the spring beams 82 may be configured with a lower naturalfrequency in order to lower the internal stresses thereof since theadditional spring stiffness provided by the resilient biasing element 57may effectively make up for s stress-reduction change to the springbeams 82. Inclusion of the resilient biasing elements 57 may also enableformation of the spring beams 82 from less stiff materials, which maydecrease primary seal device 40 manufacturing costs.

Each of the resilient biasing elements 57 may be configured as a spring.For example, the resilient biasing element 57 of FIG. 6 is configured asa coil spring. However, in other embodiments, the resilient biasingelement 57 may be configured as another type of spring (e.g., a leafspring) or another type of resilient biasing device.

The resilient biasing element 57 of FIGS. 5 and 6 is disposed radiallybetween the first mount 78 and the seal base 52. More particularly, theresilient biasing element 57 extends radially between and radiallyengages (e.g., contacts, is abutted against) the outer surface 88 andthe surface 58 of the seal base 52. However, in other embodiments, theresilient biasing element 57 may be arranged elsewhere with the primaryseal device 40. For example, referring to FIG. 7, the resilient biasingelement 57 may be disposed radially between and engage the surfaces 90and 92. In another example, referring to FIG. 8, the resilient biasingelement 57 may be disposed radially between and engage the surfaces 102and 110. In still another example, referring to FIG. 9, the resilientbiasing element 57 may be disposed radially between and engage thesurfaces 106 and 108. Of course, in further embodiments, the primaryseal device 40 may include one or more additional sets of the resilientbiasing elements 57 such that an element 57 can be arranged at all (orsome combination) of the locations shown in FIGS. 6-9 and/or otherlocations.

Referring again to FIG. 1, during operation of the primary seal device40, rotation of the rotor structure 26 may develop aerodynamic forcesand apply a fluid pressure to the seal shoes 54 causing each seal shoe54 to respectively move radially relative to the seal land surface 38.The fluid velocity may increase as a gap between a respective seal shoe54 and the seal land surface 38 increases, thus reducing pressure in thegap and drawing the seal shoe 54 radially inwardly toward the seal landsurface 38. As the gap closes, the velocity may decrease and thepressure may increase within the gap, thus, forcing the seal shoe 54radially outwardly from the seal land surface 38. The respective springelement 56 may deflect and move with the seal shoe 54 to enableprovision of a primary seal of the gap between the seal land surface 38and ribs 76 within predetermined design tolerances.

While the primary seal device 40 described above is operable togenerally seal the annular gap 30 between the stationary structure 24and the rotor structure 26, fluid (e.g., gas) may still flow axiallythrough passages 112 defined by the radial air gaps between the elements52, 54 and 82. The secondary seal devices 42 therefore are provided toseal off these passages 112 and, thereby, further and more completelyseal the annular gap 30.

Each of the secondary seal devices 42 may be configured as a ring sealelement such as, but not limited to, a split ring. Alternatively, one ormore of the secondary seal devices 42 may be configured as a full hoopbody ring, an annular brush seal or any other suitable ring-type seal.

The secondary seal devices 42 of FIG. 1 are arranged together in anaxial stack. In this stack, each of the secondary seal devices 42axially engages (e.g., contacts) another adjacent one of the secondaryseal devices 42. The stack of the secondary seal devices 42 is arrangedwith the first ring structure 44, which positions and mounts thesecondary seal devices 42 with the stationary structure 24 adjacent theprimary seal device 40. In this arrangement, the stack of the secondaryseal devices 42 is operable to axially engage and form a seal betweenthe end surface 74 of the array of the seal shoes 54 and an annularsurface 114 of the first ring structure 44. These surfaces 74 and 114are axially aligned with one another, which enables the stack of thesecondary seal devices 42 to slide radially against, but maintainsealingly engagement with, the end surface 74 as the seal shoes 54 moveradially relative to the seal land surface 38 as described above.

The first ring structure 44 may include a secondary seal device supportring 116 and a retention ring 118. The support ring 116 is configuredwith an annular full hoop body, which extends circumferentially aroundthe axis 22. The support ring 116 includes the annular surface, and isdisposed axially adjacent and engaged with the seal base 52.

The retention ring 118 is configured with an annular full hoop body,which extends circumferentially around the axis 22. The retention ring118 is disposed axially adjacent and engaged with the support ring 116,thereby capturing the stack of the secondary seal devices 42 within anannular channel formed between the rings 116 and 118. The stack of thesecondary seal devices 42, of course, may also or alternatively beattached to one of the rings 116, 118 by, for example, a press fitconnection and/or otherwise.

As described above, the assembly 20 of the present disclosure may beconfigured with various different types and configurations of rotationalequipment. FIG. 10 illustrates one such type and configuration of therotational equipment—a geared turbofan gas turbine engine 120. Such aturbine engine includes various stationary structures (e.g., bearingsupports, hubs, cases, etc.) as well as various rotors (e.g., rotordisks, shafts, shaft assemblies, etc.) as described below, where thestationary structure 24 and the rotor structure 26 can respectively beconfigured as anyone of the foregoing structures in the turbine engine120 of FIG. 10, or other structures not mentioned herein.

The turbine engine 120 of FIG. 10 extends along an axis (e.g., the axis22 or rotation) between an upstream airflow inlet 122 and a downstreamairflow exhaust 124. The turbine engine 120 includes a fan section 126,a compressor section 127, a combustor section 128 and a turbine section129. The compressor section 127 includes a low pressure compressor (LPC)section 127A and a high pressure compressor (HPC) section 127B. Theturbine section 129 includes a high pressure turbine (HPT) section 129Aand a low pressure turbine (LPT) section 129B.

The engine sections 126-129 are arranged sequentially along the axis 22within an engine housing 130. This housing 130 includes an inner case132 (e.g., a core case) and an outer case 134 (e.g., a fan case). Theinner case 132 may house one or more of the engine sections 127-129;e.g., an engine core. The outer case 134 may house at least the fansection 126.

Each of the engine sections 126, 127A, 127B, 129A and 129B includes arespective rotor 136-140. Each of these rotors 136-140 includes aplurality of rotor blades arranged circumferentially around andconnected to one or more respective rotor disks. The rotor blades, forexample, may be formed integral with or mechanically fastened, welded,brazed, adhered and/or otherwise attached to the respective rotordisk(s).

The fan rotor 136 is connected to a gear train 142, for example, througha fan shaft 144. The gear train 142 and the LPC rotor 137 are connectedto and driven by the LPT rotor 140 through a low speed shaft 145. TheHPC rotor 138 is connected to and driven by the HPT rotor 139 through ahigh speed shaft 146. The shafts 144-146 are rotatably supported by aplurality of bearings 148. Each of these bearings 148 is connected tothe engine housing 130 by at least one stationary structure 24 such as,for example, an annular support strut.

During operation, air enters the turbine engine 120 through the airflowinlet 122. This air is directed through the fan section 126 and into acore gas path 150 and a bypass gas path 152. The core gas path 150extends sequentially through the engine sections 127-129; e.g., anengine core. The air within the core gas path 150 may be referred to as“core air”. The bypass gas path 152 extends through a bypass duct, whichbypasses the engine core. The air within the bypass gas path 152 may bereferred to as “bypass air”.

The core air is compressed by the compressor rotors 137 and 138 anddirected into a combustion chamber 154 of a combustor in the combustorsection 128. Fuel is injected into the combustion chamber 154 and mixedwith the compressed core air to provide a fuel-air mixture. This fuelair mixture is ignited and combustion products thereof flow through andsequentially cause the turbine rotors 139 and 140 to rotate. Therotation of the turbine rotors 139 and 140 respectively drive rotationof the compressor rotors 138 and 137 and, thus, compression of the airreceived from a core airflow inlet. The rotation of the turbine rotor140 also drives rotation of the fan rotor 136, which propels bypass airthrough and out of the bypass gas path 152. The propulsion of the bypassair may account for a majority of thrust generated by the turbine engine120, e.g., more than seventy-five percent (75%) of engine thrust. Theturbine engine 120 of the present disclosure, however, is not limited tothe foregoing exemplary thrust ratio.

The assembly 20 may be included in various aircraft and industrialturbine engines other than the one described above as well as in othertypes of rotational equipment; e.g., wind turbines, water turbines,rotary engines, etc. The assembly 20, for example, may be included in ageared turbine engine where a gear train connects one or more shafts toone or more rotors in a fan section, a compressor section and/or anyother engine section. Alternatively, the assembly 20 may be included ina turbine engine configured without a gear train. The assembly 20 may beincluded in a geared or non-geared turbine engine configured with asingle spool, with two spools (e.g., see FIG. 10), or with more than twospools. The turbine engine may be configured as a turbofan engine, aturbojet engine, a propfan engine, a pusher fan engine or any other typeof turbine engine. The present invention therefore is not limited to anyparticular types or configurations of turbine engines or rotationalequipment.

While various embodiments of the present invention have been disclosed,it will be apparent to those of ordinary skill in the art that many moreembodiments and implementations are possible within the scope of theinvention. For example, the present invention as described hereinincludes several aspects and embodiments that include particularfeatures. Although these features may be described individually, it iswithin the scope of the present invention that some or all of thesefeatures may be combined with any one of the aspects and remain withinthe scope of the invention. Accordingly, the present invention is not tobe restricted except in light of the attached claims and theirequivalents.

What is claimed is:
 1. An assembly for rotational equipment, comprising:a seal device comprising a plurality of seal shoes, a seal base, aplurality of spring elements and a resilient biasing element; the sealshoes arranged around an axis in an annular array; the seal basecircumscribing the annular array of the seal shoes; each of the springelements radially between and connecting a respective one of the sealshoes and the seal base, a first of the spring elements including afirst mount, a second mount and a spring beam, the first mount connectedto a first of the seal shoes, the second mount connected to the sealbase, and the spring beam connecting the first mount to the secondmount; and the resilient biasing element radially between and engagedwith first and second components of the seal device, the first componentcomprising the first mount or the second mount, wherein the resilientbiasing element comprises a coil spring.
 2. The assembly of claim 1,wherein the resilient biasing element is configured to increase astiffness of the first of the spring elements.
 3. The assembly of claim1, wherein the resilient biasing element is configured to bias a firstportion of the first of the seal shoes radially away from the seal baseand a second portion of the first of the seal shoes radially towards theseal base.
 4. The assembly of claim 1, wherein the first componentcomprises the first mount; and the second component comprises the sealbase.
 5. The assembly of claim 1, wherein the first component comprisesthe first mount; and the second component comprises a mount of a secondof the spring elements that is circumferentially adjacent to the firstof the spring elements.
 6. The assembly of claim 5, wherein the firstmount comprises an inner surface; the mount of the second of the springelements comprises an outer surface radially below the inner surface;and the resilient biasing element is radially between and engages theinner surface and the outer surface.
 7. The assembly of claim 5, whereinthe mount of the second of the spring elements comprises a second mount;the second of the spring elements further includes a first mount and aspring beam; the first mount of the second of the spring elements isconnected to a second of the seal shoes; the second mount of the secondof the spring elements is connected to the seal base; and the springbeam of the second of the spring elements connects the first mount ofthe second of the spring elements to the second mount of the second ofthe spring elements.
 8. The assembly of claim 1, wherein the firstcomponent comprises the second mount; and the second component comprisesthe first of the seal shoes.
 9. The assembly of claim 8, wherein thesecond mount comprises an inner surface; the first of the seal shoescomprises an outer surface radially below the inner surface; and theresilient biasing element is radially between and engages the innersurface and the outer surface.
 10. The assembly of claim 8, wherein thefirst of the seal shoes comprises an inner surface; the second mountcomprises an outer surface radially below the inner surface; and theresilient biasing element is radially between and engages the innersurface and the outer surface.
 11. The assembly of claim 1, wherein thefirst component comprises the first mount; and the seal device furtherincludes a second resilient biasing element engaged with the secondmount.
 12. The assembly of claim 1, wherein the seal device furtherincludes a second resilient biasing element engaged with the firstcomponent.
 13. The assembly of claim 1, wherein the first of the springelements further includes a second spring beam connecting the firstmount to the second mount.
 14. The assembly of claim 1, furthercomprising: a ring structure axially engaged with the seal base; and asecondary seal device mounted with the ring structure, the secondaryseal device configured to substantially seal an annular gap between thering structure and the annular array of the seal shoes.
 15. The assemblyof claim 1, further comprising: a stationary structure; a rotorstructure; and a non-contact seal assembly comprising the seal device,the seal assembly configured to substantially seal an annular gapbetween the stationary structure and the rotor structure; wherein theseal shoes circumscribe and sealingly mate with the rotor structure; andwherein the seal base is mounted to and radially within the stationarystructure.
 16. An assembly for rotational equipment, comprising: a sealdevice comprising a plurality of seal shoes, a seal base, a plurality ofspring elements and a spring; the seal shoes arranged around an axis;the seal base extending circumferentially around the seal shoes and thespring elements; each of the spring elements connecting a respective oneof the seal shoes to the seal base, a first of the spring elementsincluding a first mount, a second mount and a plurality of spring beams,the first mount connected to a first of the seal shoes, the second mountconnected to the seal base, and each of the spring beams connecting thefirst mount to the second mount; and the spring abutted against firstand second components of the seal device, the first component comprisingthe first mount or the second mount, wherein the spring comprises a coilspring.
 17. An assembly for rotational equipment, comprising: a sealdevice comprising a plurality of seal shoes, a seal base, a plurality ofspring elements and a spring; the seal shoes arranged around an axis;the seal base extending circumferentially around the seal shoes and thespring elements; each of the spring elements connecting a respective oneof the seal shoes to the seal base, a first of the spring elementsincluding a first mount, a second mount and a plurality of spring beams,the first mount connected to a first of the seal shoes, the second mountconnected to the seal base, and each of the spring beams connecting thefirst mount to the second mount; and the spring abutted against firstand second components of the seal device, and the spring configured toincrease a stiffness of the first of the spring elements, wherein thefirst component comprises the first mount or the second mount, whereinthe spring comprises a coil spring.